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  1. #1
    Join Date
    Feb 2010
    Posts
    7

    ER Diagram for Online Result System

    hi guys..
    I have designed a ER Diagram for my "Online Result & Review System" project..
    The scenario is...
    The institute will enroll students according to the course they wish to follow..
    the students have to face exams to get the certificates and move further in the specific course. the result of the exam will be mailed to student's and there parents e mail address.

    while they are following courses they have to complete some projects to get higher gradings.

    once the project got issued they will be given a deadline. on or before the deadline date they have to submit the projects.

    for students convenience before they submitting the project they can show the project to the project supervisor and get the reviews by uploading the project in to the system.

    so according to the scenario I have designed the er diagram..
    as you all r genius in the database designing please check the diagram and guide me.....
    Attached Thumbnails Attached Thumbnails ORRS.JPG  

  2. #2
    Join Date
    Feb 2010
    Posts
    7
    i expect comments.. plz help me with ur comments

  3. #3
    Join Date
    Jun 2007
    Location
    London
    Posts
    2,527
    Quote Originally Posted by nusry View Post
    i expect comments.. plz help me with ur comments
    Hmmm - 4 hours after posting and you're already asking where the answers are! Looking at your course work and the ER diagram - I can't see where many of the fields and tables have come from:
    • where is the parents email address?
    • what does the batch table do?
    • why do you have religion in there?
    • why do you have salary?

    I haven't really spent much time into looking at this but would I be wrong in assuming that the coursework is due in the next few days, that you've just copied and pasted the coursework here and then found an ER diagram on the net and posted that? If not could you please explain the tables and fields in the diagram to us so we can better help you.

    Mike

  4. #4
    Join Date
    Feb 2010
    Posts
    7
    first of all thank you for the reply..

    the diagram is not a copy from the net.. honestly I have designed the diagram.

    I forgot to put the parent's email address, but I have mentioned about the parent's email address there. thank you for notifying my mistake.

    you asked about the batch table in the diagram. I think the batch table should be there because the institute provides lots of courses where every course may have many batches. batches are more important when it comes to the exam. because in a specific course different batches may have different date for exam.

    after you mentioning about the religion I think the religion attribute is not need for this system. so I'll remove it from the student entity as well the Salary attribute from the lecturer entity.

    apart from these are there any mistakes in my diagram. if it so plz notify me.

  5. #5
    Join Date
    Jun 2007
    Location
    London
    Posts
    2,527
    Just some points I came up with at random:
    • I don't see a certificate table. You have batches and exams which weren't mentioned in your "spec" but no certificates.
    • Result table contains Subject_1, 2, 3 etc - this is not in third normal form.
    • Why do you have so much data on lecturer when it's outside the boundary of the question?
    • It's unclear (to me) in your diagram whether a student can have > 1 project or whether this should be the case.
    • How do you tell which lecturers run which courses?
    • How do you tell which lecturers should be marking which projects?
    • How does the department_num_staff field get worked out and should it be there at all?
    • Shouldn't there be dates in some tables?
    • Why do you need a result_id field?
    • What's the difference between a student_nic and a student_id?

    I'm not saying you're wrong but I think you should consider the above points. There may well be other issues but I didn't spend too long going over our design.

    Mike

  6. #6
    Join Date
    Feb 2010
    Posts
    7
    tnx mike...
    I'll make relevant changes and re upload the diagram.
    because am a new bee to these diagram.

  7. #7
    Join Date
    Feb 2010
    Posts
    7

    Modified Version of the Diagram

    I re-uploaded the modified diagram..
    please have a check.

    I think the certificate entity not much important since the system won't provide details about certificate.

    have a look on the new diagram
    Attached Thumbnails Attached Thumbnails ORRS version 2.JPG  

  8. #8
    Join Date
    Jun 2007
    Location
    London
    Posts
    2,527
    Quote Originally Posted by nusry
    have a look on the new diagram
    Some of the previous issues have been addressed but many haven't. The main issue for anyone reading your spec and then looking at your ER diagram is that you mention certain entities and then don't show them in the diagram while other entirely new entities creep in - ie certificates don't appear and batches do. The overall design seems to cover most aspects of what you mentioned but the database structure appears confused (to my eyes) ie why do we have English, MS Office fields in the results table?

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